Gripping mechanisms for wire-tying machines



April 24, 1956 F. H. LAMB 2,743,081

GRIPPING MECHANISMS FOR WIRE-TYING MACHINES Filed April 25, 1955 2 Sheets-Sheet 2 GRIPPING'MECHANISMS FOR WIRE-'TYING MACHINES Frank .H. Lamb, .Hoquiarn, Wash, assignor to Ovalstrapping 'Inc., Hoquiam,Wash., a corporation of Washington ApplicationApril 2s, 1955, Serial No. 503,703 4 Claims. Cl. 254-51 Another disadvantage of some. .prior arrangements is 7 that 'the released wire-end is left projecting outwardly from the tied package, resulting .in 'hand injuries or damage to other packages; TooVercome this second disadvantage various proposals have been put forward, a

mainly based on kinking the Wire to direct the terminal portion thereof downwardly towards the package at .a small angle to the plane of-surface where the .tie'is located. Many of these proposals have failed to .giveconsistent'ly satisfactory results, however, since, while they usually successfully kink the wire-end, the kink :produced is not infrequently destroyed during the release of the'gr'ipping jaws preparatory to withdrawing the machine from the .tie.

After considerable study and experimentation, I have discovered that these disadvantages could be entirely avoided by resort to a sliding finger member arranged for interpositioning between (a) the element carrying the lower gripping surface, and (If) a special stop member, as said gripping surface .is carried towards its .final gripping position. v

While the discovery "just mentioned is the basis for the present invention, the essence of the invention would be better defined as follows: a wire-end gripping mechanism for a wire-tying machine which includes a flat vertical surface for *the 'mounting'of said mechanism; said mechanism comprising a fixed stub shaft extending outwardly from said'surface at right angles thereto; a generally rectangular anvil-carryingblock rotatably mounted on said.

s'tub shaft; 'an anvil integral with said block extending outwardly from the base of said hlock substantially at right angles thereto; first stop means extending 'outwardly from said machine on one side of said blo'clc' and adjacent the bottom thereof to limit rotary movement of said block in one directionysecond 'stopmeans secu'redto said flat vertical surface 'on the other side of said block and adjacent the bottom thereof "to limit the rotary movement at said block in the other direction; biasing means at- "tadhed to "the upper end of said block to urge the anvil carrying block torest against said second stop means; a *spring loaded "finger slida'b'ly mounted on said "flat 'veritical "surface above said second step means and arranged to slide-into an intervening position between said block and ree 2 mediately adjacent .said first stop means; an operating lever rotatably mounted on said stub shaft outwardlyof said block; a wire-gripping element secured tothe lower end of said operating lever, said element having a projecting portion which extends outwardly from .said operating lever on the side thereof adjaeentsaid secondstop means; and a projection onrsaid slidable fingerlocatedifor lifting engagement by the projecting portion of said wiregripping element, whereby .said spring-loaded .s-lidable finger may, through actuation of said operating lever, be forced out of the said intervening position despite the spring-loading of the finger.

1n drawings illustrating the presently preferred embodiment of the invention: H

Figure 1 is a front elevation showing the wire gripping mechanism in its initial position. p p

Figure 2 .is a view similar to Figure :1 except forthe fact that it shows the mechanism in the wire gripping Figure 3 .is an exploded perspective view'showing some parts which are not adequately illustrated by Figures '1 and 2 alone, n I

Figure 4 is a perspective view of the .operat'inglever, and i Figure 5 is a fragmentary detail showing portions of the operating lever and anvil-carrying block. Q

In these drawings, reference character 10 generally indicates a wire-tying machine. The drawings only show the end of the machine where the invention is applied since the remainderofthe'machine may be of quite conventional construction. and its inclusion -would entail "an undesirable cramping of the scale of the drawings. The illustrated end of the machine is provided with .a flat vertical surface 11 for the mounting of the novl 'w'ire end gripping mechanism. Afixed stub "shaft 1'2 extends outwardly from surface 11 at "right angles thereto; L An anvil-carrying block 13 of generally rectangular vertical and transverse cross-section is rotatably mounted on stub shaft 12 by virtue of a bore-which extends through the block in the generally central region thereof. An anvil 14, integral with the block 13, *eXtendsnutwardly from the base thereof, the anvil being disposed substantially at right angles to said block.

*Sinc'e anv'il 14 is to "play the part of-the lower gripping element, the shape 'of the upper surface of the anvil is important. From Figure '3 it may be noted that the anvils upper surface consist-s of'thre'e 'liat regions'each "said second stop means when said "block'has been rotated,

against the action -of-said biasing means, to apoint imfeaturing a different *slope. To be more specific, a ilat triangular region 15, which "is substantially horizontal When the block 14 is in its initial (Figure 1' position, extends outwardly from 51061414; a flat"tria-ngular region 16 sl'opes downwardly and towards the centre ofdhe machine'it) at a marked angle to region 15; andaflat region 17 slopesdownwardly and outwardly from region 15. The reasons for providing the difierently sloped regions 15, 1 6 and .1 7, will be more fnlly pointed-out later on. p f

' The wire-tying machine 10 has a i'conventionalfslotted arrangement 18 for holding 'the overlapped lengths of wire during their .=intertwisting to form the wire itiei The end wall of :arrangement .18 WhldhdllGS mearest thegripping mechanism has zbeenllabelle'd 19 and-constitutes a stop :means limiting notation of the anvil-carrying .block- 13 in one .direction. This end .19awhich acts as a stop is referred .to .as a ffi-rst stop means in the accord, panying claims-q a A second stop means is provided to limit rotation of the "anvil-carrying block '13 in the other direction. fl'his second stop means, which has been labelled "20in the drawings, is 'adjustalily, "removably, secured to 'fla't stir-- face '11 andextends outwardly'therefrom at a point adjacent the bottom of the block "13 and on the opposite side of the block from the stop 19. Stop is a rectangular-block which is pointed at one-end, and is pointed downwardly at an angle of about 30 degrees ho horizontal. The upper of the two faces which form the point has been labelled 21 and is seen to be generally vertically disposed. Attention is invited to the recessing of the upper surface of the stop 20 to provide a more sharply sloped region 22 which leads into point-forming face 21 but is only located in the outermost half of the upper surface of the stop block.

A tension spring 23 is stretched between a fixed pin 24 extending outwardly from surface 11 and a. pin 25 extending upwardly from the upper end of anvil-carrying block 13. Tension spring 23 is a biasingm'eans which urges anvil-carrying block 13 to rest against surface 21 of stop means 20, the so-called second stop means."

A spring-loaded finger 26 is slidably mounted on the surface 11 above second stop means 20 and is disposed at an angle of approximately 60 degrees to horizontal. The slidable mounting is achieved by means of a longitudinal slot 27 which extends through the finger at the upper end thereof and a fixed pin 28 which extends outwardly from surface 11 and is provided with an enlarged head to retain the finger against surface 11. The springloading is effected by means of a compression spring 29 set in a central bore in the finger and bearing against the base of said bore and the pin 28. Spring 29' urges opposite sides of the lower end of the finger 26 to contact the second stop means 20 and the adjacent side of the block 13. A pin 39 projects outwardly from finger 26. The function of pin 30 will appear later on when the functioning of the slidable finger is being described.

An operating lever 31 is rotatably mounted on stub shaft 11 by means of a transverse bore 310 extending through the lower portion 32 of the lever. Lever 31 is provided with a spherical handle 33. The lower portion 32 of operating lever 31 is of rectangular transverse cross-section. A rectangular recess 34 is provided on the inner side of the lever in the corner thereof nearest stop means 20. The cutting of recess 34 is effected so as to leave a pin-like element 35 for the mounting within the recess of a generally rectangular wire-gripping element 36 having gripping teeth along its lower edge 37. Some clearance, as indicated at 38, is left between the wire-gripping element 36 and the confining walls of the rectangular recess 34, so that the element is permitted a few degrees of rotation about its supporting pin 35. Wire-gripping element 36 has a projecting portion 39 which extends beyond the side of the operating lever 31 on the side thereof adjacent second stop means 20. Projecting portion 39 is bluntly pointed and has a straight-line upper edge 40.

Above the bore 31a, a bore 41 extends through the operating lever 31 at right angles to the bore 31a (see Figures 3 and 5). A tension spring 42 is accommodated by bore 41 and is stretched between a screw 41/: set in the operating lever at one end of the bore and a hooked element 43 which is attached to the opposite end of the spring and seated in a retaining recess 44 provided in anvil-carrying block 13. It can readily be seen that tension spring 42 is a biasing means which urges the operating lever 31 to rotate about the stub shaft 12 in a direction which brings the toothed lower edge 37 of wire gripping element 36 into contact with the anvil 14.

A stop 45 is rigidly secured to surface 11 at a point substantially vertically above first stop means 19, and functions to limit rotation of the operating lever 31 in one direction. Rotation of the operating lever in the other direction is limited by first stop means 19 which acts through anvil-carrying block 13 and wire-gripping element 36 to impose the limitation. V

Having provided a full structural descriptionof one embodiment of my invention, I will now proceed with a description of its operation.

A length of tying wire sufficient to tie a given package is drawn off a suitable supply reel and caused to encircle the package with the free end of the wire introduced in the novel end-gripping mechanism, with two portions of the wire extending beside one another through the slotted arrangement 18 where the tying mechanism proper is located, and with the reel end of the wire passing through a tensioning mechanism (not shown). The point of interest here will. of course be the mode of introduction of the wire-end into the gripping mechanism. The wire-end is passed along the flat region 15 of anvil 14, with the side of the wire pressing against the outer surface of block 13, until the extreme end of the wire contacts recessed portion 22 of stop means 29. it will be understood that during this step the anvil block 13 bears against stop means 20, and is held there by spring 23. It will also be appreciated that the introduction of the wirecnd through the gripping mechanism forces a small amount of rotation of the operating lever 31 (in the 0pposite direction to the arrow B), since the introduction involves raising wire-gripping element 36, which in turn causes rotation of the operating lever, against the action of the spring 42 which normally urges element 36 into contact with surface 15 of anvil 14. The gripping teeth on the lower edge 37 of gripping element 36 are directed to permit sliding of the wire in the direction of stop 20, but to bite into the wire when it is drawn in the opposite direction. Such teeth are well-known and need no further description.

Having thus inserted the wires end, the course of wire which encircles the package may be tensioned about the package. The tensioning procedure involves unitary rotation of the lever 31 and the block 13 until they are both halted by the anvil-carrying block striking against first stop means 19. As this movement of the anvilcarrying block takes place, the spring-loaded finger 26, whose lower end bears against both the anvil block and the inclined upper surface of stop means 22, slides downwardly under the influence of the spring 29 and interpositions itself between the anvil block and the substantially vertical face 21 of the stop block 20. It will be noted that the finger is, in effect, a spring-powered wedge which is driven home as the anvil block meets the stop means 19, and prevents rotation of'the anvil block in the opposite direction until such time as the finger is lifted out of its wedging position. It is perhaps now timely to point out that the leading edge of the finger 26 is cut away at 46 to assist this sliding-wedging action.

During the tensioning procedure the wire, since it is both gripped between element 36 and surface 15 of anvil 14 and confined within the slotted arrangement 18, is bent over the ridge which exists between regions 15 and 16 of the upper surface of anvil 14. The wire-end is drawn so tightly across the ridge just mentioned that a definite kink is imparted in the wire. Slippage of the gripped wire end after tensioning is virtually ruled out by the action of teeth of edge 37 in conjunction with the positioning of the anvil. In the locked position, the ridge between surfaces 15 and 16 of the anvil is raised above the course of the wire through slotted arrangement 18, and the surface 15 slopes downwardly and outwardly from said ridge, so that the more the wire is tensioned the more strongly do the teeth bite into the wire and clamp it between the gripping element and the anvil.

Once the wire has been tensioned, the conventional twisting operation would be performed to effect the tie, and the reel end of the wire would be cut-off. This would complete the operation except for release of the wireend preparatory to withdrawal of the tying machine. The wire-end is released simply by actuating lever 31in the opposite direction to the arrow B. Quick release is achieved since the gripping element 36 is lifted clear of the anvil while the latter isstill held against stop 19. Furtherlitting, i. e. further rotation of the lever, causes edge 40 of gripping element 36 to contact pin 30 and raise slidable finger 26, against the action of spring 29, out of wedging position; whereupon the anvil block 13 is immediately driven by its spring 23 into contact with stop means 20. The gripping mechanism would then be ready for gripping a new wire end. Withdrawal of the machine is facilitated by the earlier-described slope of region 17 of the anvil. The kink imparted by tensioning the wire over the ridge between anvil regions 15 and 16 is not disturbed by the releasing and withdrawing steps, and positions the wires end in the desired safe manner.

What I claim as my invention is: l. A wire-end gripping mechanism for a Wire-tying machine which includes a flat vertical surface for the mounting of said mechanism; said mechanism comprising a fixed stub shaft extending outwardly from said surface at right angles thereto; a generally rectangular anvil-carrying block rotatably mounted on said stub shaft; an anvil integral with said block extending outwardly from the base of said block substantially at right angles thereto; first stop means extending outwardly from said machine on one side of said block and adjacent the bottom thereof to limit rotary movement of said block in one direction; second stop means secured to said flat vertical surface on the other side of said block and adjacent the bottom thereof to limit the rotary movement of said block in the other direction; biasing means attached to the upper end of said block to urge the anvil-carrying block to rest against said second stop means; a spring-loaded finger slidably mounted on said flat vertical surface above said second stop means and arranged to slide into an intervening position between said block and said second stop means when said block has been rotated, against the action of said biasing means, to a point immediately adjacent said first stop means; an operating lever rotatably mounted on said stub shaft outwardly of said block; a wire-gripping element secured to the lower end of said operating lever, said element having a projecting portion which extends outwardly from said operating lever on the side thereof adjacent said second stop means; and a projection on said slidable finger located for lifting engagement by the projecting portion of said wire-gripping element, whereby said spring-loaded slidable finger may, through actuation of said operating lever, be forced out of the said intervening position despite the spring-loading of the finger.

2. A wire-end gripping mechanism as defined in claim 1, including stop means for said operating lever disposed generally vertically above said first stop means.

3. A wire-end gripping mechanism as defined in claim 1, including biasing means urging said operating lever to rotate in a direction which brings said gripping element into contact with said anvil.

4. A wire-end gripping mechanism as defined in claim 3, in which both said biasing means utilize a tensioned spring arrangement.

No references cited. 

